There are occasions when there is a need to shape the end of an elongated workpiece by holding it against a revolving shaper. For instance, practitioners of electric arc welding are aware of the problems encountered when the point of a non-consumable metal electrode (such as tungsten or carbon) becomes eroded by the intense heat of the spark which occurs when electricity is caused to deliberately form an arc from the pointed end of the electrode rod to the site where welding is performed. The ionizing action of the electric arc produces very high temperatures at the tip of the electrode and causes erosion of the point. Practitioners find that they need to re-sharpen the rod frequently in order to cause the spark to be uniform and avoid stray sparks. When working in the field, away from a well-equipped and well-supplied shop area, the practitioners find it difficult to re-sharpen the end of a worn electrode and still maintain an efficient rate of welding. It has been customary for the welder to find a way to hold the welding rod against a grinder while trying to maintain a constant angle and pressure of the rod against the revolving grinder so as to form a uniformly shaped point aligned exactly with the axis of the rod. The usual field practice has been to hold the rod with a welding glove or other heat resistant item while trying to manually revolve the rod itself in order to get the proper shape; this is a time consuming procedure due to the difficulty of quickly obtaining a good point. Furthermore, the grinding causes the rod to get very hot, requiring that it be often cooled by immersing it in water or some other cooling liquid before continuing the grinding. Also, there is a tendency of the electrode to be pulled out of the welder's glove by the considerable friction caused by the grinding activity. Difficulty in grinding by hand often causes not only loss of time, but also waste of the expensive tungsten metal of which the rod is comprised.
A device which has been suggested (U.S. Pat. No. 4,575,971) in recent years is the use of a relatively thick metal round bar having a hole completely bored through its center from end to end; the hole is only slightly larger in diameter than the electrode and the electrode is intended to spin in the bore when in contact with a grinder. A number of holes are drilled into the round bar at preselected locations in a row along the bar, normal to, and communicating with, the axial bore. A screw with a blunt rounded nib on its end is placed in the hole selected by the operator of the device and an electrode is slid into the bore as far as permitted by the nib of the screw. The inserted welding rod, when held against a grinder will revolve within the bore by the grinding activity, but the same activity which causes the welding rod to revolve against the grinder also tends to pull the rod out of the bore. The nib on the end of the screw serves to limit the extent to which the rod is inserted in the bore, but does not hold the revolving welding rod from being pulled out of the bore by the revolving action of the grinder. Furthermore, the use of a nib to block the inserted end of the electrode which is in the bore could cause undue wear on the revolving electrode if that inserted end had been sharpened to a fine point.
It is an object of this invention to provide a device for holding an elongated workpiece against a revolving shaper whereby the device permits the elongated workpiece itself to be revolved by the action of the revolving shaper, but does not permit the revolving shaper to pull the elongated workpiece from its holding device.
It is also an object of this invention to provide a method for creating an essentially symmetrical shape on an end of an elongated workpiece whereby the elongated workpiece is removably fastened within a device which is easily held by hand some other cooling liquid before continuing the grinding. Also, there is a tendency of the electrode to be pulled out of the welder's glove by the considerable friction caused by the grinding activity. Difficulty in grinding by hand often causes not only loss of time, but also waste of the expensive tungsten metal of which the rod is comprised.
A device which has been suggested (U.S. Pat. No. 4,575,971) in recent years is the use of a relatively thick metal round bar having a hole completely bored through its center from end to end; the hole is only slightly larger in diameter than the electrode and the electrode is intended to spin in the bore when in contact with a grinder. A number of holes are drilled into the round bar at preselected locations in a row along the bar, normal to, and communicating with, the axial bore. A screw with a blunt rounded nib on its end is placed in the hole selected by the operator of the device and an electrode is slid into the bore as far as permitted by the nib of the screw. The inserted welding rod, when held against a grinder will revolve within the bore by the grinding activity, but the same activity which causes the welding rod to revolve against the grinder also tends to pull the rod out of the bore. The nib on the end of the screw serves to limit the extent to which the rod is inserted in the bore, but does not hold the revolving welding rod from being pulled out of the bore by the revolving action of the grinder. Furthermore, the use of a nib to block the inserted end of the electrode which is in the bore could cause undue wear on the revolving electrode if that inserted end had been sharpened to a fine point.
It is an object of this invention to provide a device for holding an elongated workpiece against a revolving shaper whereby the device permits the elongated workpiece itself to be revolved by the action of the revolving shaper, but does not permit the revolving shaper to pull the elongated workpiece from its holding device.
It is also an object of this invention to provide a method for creating an essentially symmetrical shape on an end of an elongated workpiece whereby the elongated workpiece is removably fastened within a device which is easily held by hand and which allows the elongated workpiece to become shaped by a revolving shaper as the workpiece is itself revolved, but is not permitted to be pulled from the device by the revolving action.
Yet another object is to provide a device which can be used to shape both ends of a workpiece, since the present device permits a shaped end to be inserted into the device without it becoming damaged when the other end of the workpiece is positioned in the device for shaping on a revolving shaper.
Still another object is to provide an essentially lathe-quality shaping of the end of a workpiece by employing the present device.
While the present descriptions and teachings are directly mainly to shaping of metal workpieces, especially welding rods, it will become apparent to others, upon reading the present disclosure, that the present device can be used for other elongated workpieces. Also, the revolving shaper may be a cutting, grooving or smoothing device as well as a grinder referred to in this disclosure.